Impulse Engine

An impulse engine (internally metered pulse) is a nuclear fusion-based propulsion system used primarily for sub-light travel. Each impulse engine consisted of one or more nuclear fusion reactors, a series of subspace field coils, and a vectored thrust nozzle to direct the plasma exhaust. The engine produced a high energy plasma that was vented out of the thrust nozzles to propel the starship. In the event of an emergency while at warp, the impulse engines could also be utilized to temporarily generate a Warp field to maintain warp speed for the vessel or the primary hull in the event of Saucer separation. (ST reference: USS Enterprise Owners' Workshop Manual) The deuterium-based fusion reaction of the impulse drive also served as a secondary power system for a starship, and was utilized for powering internal systems. (TNG reference: Star Trek: The Next Generation Technical Manual)